Driver for rotary tools



Sept. 7, 1937. R..s. BLAIR DRIVER FOR ROTARY TOOLS Filed Nov. 18, 1952 2 Sheets-Sheet 1 INVENT Sept. 7, 1937.v f R s; BLAlR 2,092,598

DRIVER FOR ROTARY TOOLS Filed Nov. 1.8,` 1952 2 Sheets-Sheet 2 MM Q Patented Sept. .7, 1937 UNITED STATES Paxil-rrr oFFIcE- naiven Fon no'rAn'Y ,Toots Robert S. Blair, Stamford, Conn. Application November 18, 1932, Serial No. 643,138

12 Claims.

This invention relates to rotary tools and more particularly to hand tools such as screw drivers, drills, and the like.

One of the objects thereof is to provide driving means for such tools 'of simple and practical construction and adapted effectively to meet varying conditions of use. Another object is to provide means of the above nature of eiiicient and dependable action at all stages of its use. Other objects are to provide means of the above nature characterized by convenience in use, speed in work, and economy of manual eilort.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts all as will be illustratively herein described and the scope of the application oi'I which will be indicated in the appended claims.

In the accompanying drawings in which are shown one or more of Various possible embodiments oi the several features of this invention,

Figure l is a sectional elevation of one of the Same;

Figure 2 is a plan oi a supporting member in extended position;

Figure 3 is a sectional plantalien along the line Figure 4i is an elevation, partly in section, of another device; l

Figure 5 is a sectional elevation of a construction Figure (i is a sectional plan taken along the line lli-t of Fig. 5;

Figure is a detailed elevation of a cam member forming a part oi the device shown in Fig. 5; and

Figure 8 is a sectional plan taken substantially along the line tof Fig. 5.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring now to Figure l of the drawings, there is shown at It) a. tool which may be considered a screw driver and theshank of which extending upwardly terminates in a stud of reduced diameter at Il which rotates freely in a plate i2. Fixed upon the shank is a pinion I3 which clears the plate I2 due to the engagement with the latter of the shoulder formed by the stud II. The tool I0 is provided with a shoulder It bearing against a squared member I5 xed upon the lower end of a casing part It. The upper edge of this casing member is inwardly offset modified as at II and threaded into engagement with the inner surface of the lower edge of a casing member` I8. Thus the outer surface of casing members I6 and I8 are substantially flush and are knurled as indicated at I9. The upper edge of casing member I8 is provided with a shoulder 20 against which rests the depending flange 2| of the lower edge of a casing member 22 having a rounded, closed top 23 and a knurled outer surface as indicated at 2t.

Fixed within the lower portion of casing member 22 is the plate I2. Opposite this plate and resting snugly but freely within the upper portion of the casing member I8 is a support 25. This member is shown in flat form in Fig. 2 of the drawings and comprises a central plate 26 with a pair of short extensions 2l. It is also provided with an extension 2t adapted to be bent along the dotted lines so as to have a portion resting smoothly and rotatably within the casing and a portion parallel to the plate with a hole 29 opposite a hole 3l) in the plate.

On the opposite side of the plate is an extension 3l similarly adapted to be bent along the dotted lines so as to bring its opening 32 opposite the f,

opening 33 in the plate. Opening3t is provided as a bearing forl the upper portion of the shank of tool It.

With the various arms of the member 25 all bent downwardly in parallel position there is formed a member adapted to support rotary and securing parts therein and the inwardly bent ends of the arms 28 and 3l take the position shown in Fig. 1 of the drawings.

Meshing with pinion I3 is a pinion 35 mounted upon a short shaft 36 and having reduced ends respectively journaled in the plate I2 and in the opening 29. This part also has an intermediate bearing in the opening 30 of the plate 2S.

A shoulder screw 3l passes through the openings 32 and 33 and is tapped into the plate l2 as shown in Fig. 1 of the drawings.

The pinion 35 meshes with an internal gear 38 which is fixed within the upper edge of the casinglt. i

In the use of this device as a screw driver the screw is started inthe usual way and the casing member I8 held stationary, the screw being driven through turning of the casing member 22. In this manner the pinion 35, being revolved about the axis of the screw driver l2 and meshing with the stationary rack 38, rotates the pinion I3 and the tool with an angular speed which may be several times that of the casing member 22. When the screw is nearly driven Lil) Cil

and requires additional torque the casing members I8 and 22 are turned together in the same direction and there is then no multiplication of speed of the tool as compared to the casing members as the gears are virtually locked.

When it is desired to draw a screw the extra torque is gained by turning the casing members I8 and 22 together, as above described, although in the opposite direction to unseat the screw. This may be done by grasping both casing members in a single hand or by the use of two hands. After the screw is loosened it is quickly withdrawn by holding the casing member I8 stationary and turning the casing member 22 in an unscrewing direction, thus multiplying the speed in the opposite direction and speedily drawing the screw.

The thrust of the parts may be taken by the meeting edges of the casing members I8 and 22 and transmitted through casing member I6 and shoulder I4 to the tool, thus leaving the gears uncramped. Lubrication is readily accomplished by inserting oil through an opening 39 and the lower portion of the casing member I6. If it is desired to disassemble the parts a screw-driver is inserted through this opening 39 and the screw 3l withdrawn, whereupon the casing section I6 is unscrewed from the casing section I8 by, use of the squared shoulder or nut I which is secured to part I6. All of the mechanism is then removed through the lower end of the casing I8 and may be reassembled by reversing this step.

Turning now to the construction shown in Figure 4 of the drawings, there is indicated diagrammatically at 40 a screw-driver of the type in` which the reciprocation of a handle in the direction oi thrust of the tool will by utilizing spiral threads or like elements cause a rotary movement of the tool in one or the other direction by suitable selective mechanism. Tools of this sort are so well known that a detailed description or showing is unnecessary and it is to be understood that although the several devices are herein referred to as screw-drivers, nevertheless they may be adjustably employed for driving drills and other tools.

The device of Figure 4 comprises a driven part 4I which may either be formed directly on the spirally threaded shank of the driver 40 or may be inserted in and driven by the chuck 42 which may form a part of the tool mechanism 40. With one arrangement a duplication of chucks is avoided, and with the other arrangement the device may be used as an attachment for complete tool drivers by substituting the part 4I for the tool.

The shank 4I has fixed thereon a pinion 42 of the spur type but with the lower ends of its teeth pointed as indicated at 43 to facilitate endwise meshing with a pinion 44 whose teeth may likewise be pointed at their upper ends.

On shank 4I beneath the pinion 42 is a squared shoulder or locking member 45 and an extension of the shank downwardly passes through a chamber 46 and slidably fits into a recess 41, being urged upwardly by a heavy spiral spring 48.

The chambers 46 and 41 are formed in a fitting 49 which is provided with an upper plate-like portion 50 having a depending fiange 5I. The opening in plate 5I)v in which the squared portion 45 rests fits the same so as to prevent relative rotary movement of these parts when in this position.

Rotatably fitted about the flange 5I is an outer casing 52 having fixed therein an internal gear 53 meshing with the pinion 44. The upper end of this casing may curve inwardly and thence downwardly, as indicated at 54, to serve as a bearing for the shank 4I and as a stop to limit its upper movement. For convenience in assembling the parts this casing may have a slightly annular depression, as indicated at 55, and between this depression and the gear 53 is an annular plate 56 adapted to turn with the plate portion 50. The gear 44 is mounted upon a pin 51 journaled at its ends in the plate member 50 and the ring 56 and a large shoulder screw 58 serves to hold these parts in stationary relation, additional screws of this sort being provided if found necessary to give a more rigid connection.

Secured to or formed on the fitting 49 is a chuck 59 adapted to receive the screw-driver or other tool 68.

Considering now the action of this device, the shank 4I ls rotated or driven by the parts to which it is secured here illustratively and diagrammatically shown` as a thrust controlled mechanism utilizing spiral recesses or threads reversely cut whereby the driven part is rotated in one or the other direction by the thrust of a handle axially thereof.

In the normal use of the device with a moderate thrust the shank 4I acting through the squared portion 45 slidably fitted in a corresponding recess in the plate 58 rotates the latter part and thereby drives the chuck 59 and tool 60. When, however, an unusual torque is required, as in finishing the driving of a screw or unseating a screw which is firmly fitted, the thruston the driving handle automatically becomes greater in the effort to overcome the resistance. This increased thrust compresses the spring 48 and permits gear 42 to slide into mesh with the pinion 44 and, with a slightly greater sliding movement, the squared part 45 passes into the recess 46 in which it may :freely revolve. At this Stage the outer casing 52 is firmly seized and held against rotation by its knurled outer surface. Gear 42 then drives the pinion 44 and the latter rolls along the then stationary rack 53. The revolution of pinion 44 about the axis of the shank 4I carries with it, at a relatively low speed,

the plate 50, and hence the fitting 49 and tool 60 driven thereby. This action, giving a relatively slow angular speed in proportion to that of the shank 4I, correspondingly increases the available torque to overcome the assumed abnormal resistance to movement, and upon this resistance decreasing the spring 48 overcomes the lessened thrust and forces the rotating squared part 45 back into its recesses. With this movement the gears 42 and 44 are unmeshed and the original direction high speed drive is resumed.

The parts are readily disassembled by the removal of the screw 58 and the flanges 54 and 5I slide respectively with respect to the shank 4I and the casing 52. It may here be noted that in the action of the device these cylindrical flanges serve as bearings and increase the stiffness as well as facilitate the driving action.

Referring now to the device shown in Figures 5 to 8 inclusive of the drawings, there is shown a driving member 6I which is pinned or otherwise secured to a fitting 62. The latter part, having a cylindrical outer surface, is slidably fitted within a casing 63 flanged inwardly at the top as shown at 64. The casing 63 has tted into its lower end and secured thereto a fitting 65 which is in turn secured to the chuck 66 adapted to receive and drive the tool.

The fitting 65 isprovided with a cylindrical wall 61 to receive the lower extension 68 of the spindle/Bl/which slides in a chamber 69. This ed to receive the lower end of a heavy spiral spring 1I the upper end of which rests within a recess 12 formed in the fitting 62. The shank 6I is driven by a spirally threaded mechanism such asis illustratively shown and has been described in connection with the embodiment of Figure 4. The rotation of this shank driving the fitting 62 also drives the casing G3, and, through the parts hereinbefore described, the tool in the chuck 66. This drive of the casing is normally` effected through a pair of lugs 13 formed at the lower end of the fitting adapted respectively to engage inwardly directed pins 14 secured to the inner walls of the casing 63. These lugs 13 on engaging the pins M drive the casing, and upon the motion being reversed the lugs respectively travel in the opposite direction so that each lugv 13 will then engage the opposite lug 14, this lost motion occurring only on a reversal of the direction of-drive.

If, now, the resistance to turning of the tool increases to a sufllcient extent the thrust will be correspondingly increased and there will be a tendency to compress the spring H with adown" ward sliding of the tting 62. This tting is provided with four slightly spiral grooves, each adapted to accommodate one of the pins 14. For one lug 13 there are grooves 15 and 16, as shown in Figures 6 and 7 of the drawings, andfor the other lug 13 there are provided similar grooves l1 and 13. If, at the assumed time the thrust be sufficient to overcome the spring, one of the pins 'M will enter the groove 18 and the other pin 1li enter the groove 15, assuming that the rotation of the lug 'i3 is in the direction indicated by the arrow in Figure 6. The travel of these pins through these gradually inclined grooves will give a slight rotary movement with increased force, the pins being provided with rollers to reduce friction, if desired. It will be understood that if the driving is in the opposite direction at this stage the two pins will enter the channels or grooves it and 'l1 with a similarly increased torque in the direction of drive. In this manner at the desired time the torque is automatically increased to any desired degree, depending upon the inclination of the various grooves. The slant of these grooves may, perhaps, be better understood from the slightly higher section shown in Figure 8 of the drawings.

' It may here be noted, in order that certain terms may better be understood, that the term tool is used throughout the following claims with a broad signicance to include the tool itself or any part thereof, and that terms such as chuok" and handle are also broadly employed. It may also be noted that the expression eort-controlled means a control through the,

driving eiort whether it be thrust, torque, or

' otherwise.

1. In a device of the general nature of that herein described, in combination, a handle, a rotary tool, means adapted to drive said tool from said handle, and means adapted automatically `to increase the ratio of the torque imparted to said tool to the actuating effort upon said handle, said last mentioned means being actuated by the tool-rotating force.

2. In a device of thegeneral nature of that herein described, in combination, a handle, a tool, means adapted to drive said tool from said handle, and means adapted automatically to alter the torque imparted tosaid tool with a given lactuating effort upon said handle, said last means being automatically controlled by the driving effort, imparted to said tool and operated upon the same reaching a certain value.

f 3. In a device of the general nature of that herein described, in combination, a handle, a tool, means adapted to drive said tool from said handle, and means adapted automatically to alter the torque imparted to said tool4 with a given actuating eiort upon said handle, said v last means being controlled by the manual driving pressure upon said handle.

4. In a device of the general nature of that herein described, in combination, a tool, a driving mechanism 4for said tool comprising a member manually actuated toward and away from said tool and adapted thereby to -rotate said tool, and means adapted to increase the ratio of the torque imparted to said tool to the pressure upon said member.

5. In a device of the general nature of that herein described, in combination, a tool, a driving mechanism for said tool comprising a member manually actuated toward and away from said tool and adapted thereby to rotate said tool, and means adapted to increase the ratio of the torque imparted to said tool to the pressure upon said member, said last means being rendered effective by abnormal pressure upon said member.

6. In a device of the general nature of that herein described, in combination, a tool, a rotary member, means comprising a manually actuated member adapted upon' movement thereof longitudinally of said rotary member to rotate the same, means adapted to drive said tool from said rotary member, a second member adapted to drive said tool from said rotary member at a. dierent rate of speed, and automatic means controlled by driving effort and adapted to shift the drive from one to the other of said driving means member adapted upon movement thereof longitudinally of said rotary member to rotate the same, means adapted to drive said tool from said rotary member, a second member adapted to drive said tool from said rotary member at a dierent rate of speed, and means adapted to shift the drive from one to the other of said driving means, said last means being controlled by longitudinal pressure upon said manually actuated member.

8. A portable tool comprising a chuck, a device adapted for connection with said chuck and provided with a chuck adapted to receive a tool, said device comprising means adapted to vary the ratio of the torque upon said tool to the driving force and said tool being shaped to be fitted within said first chuck.

9. In a device of the general nature of that herein described. in combination, a tool. a manually actuated driving member, means adapted to drive said tool from said driving member at a plurality of rates of speed, and means actuated by the driving movement of said driving member adapted to change from one to the other of said speeds of drive.

10. In a device oil the general nature of that herein described, in combination, a tool, a driving member movable in a direction longitudinal of'said tool, means connecting said driving member with said tool to drive the saine'and comprising a plurality of slots of different pitch, and means coacting with said slots and adapted alternatively to drive by the cam action of said slots whereby the rate of rotation of said tool is varied with a given rate of movement of said member. x

11. In a device oi' the general nature of that herein described, in combination, a tool, a driving member movable in a direction longitudinal oi' said tool, means connecting said driving member with said tool to drive the same and comprising a pluralityof slots oi din'erent pitch, means coacting with said slots and adapted alternatively to drive by the cam action of said slots whereby the rate of rotation oi' said tool is varied with a given rate of movement of said member, and means adapted to bring said slots into and-out ot action in accordance with the pressure exerted upon said rst member.

12. In a device of the general nature oi that herein described, in combination, a rotary tool, a rotary driving member, means comprising a pair of relatively longitudinally movable parts respectively connected with said driving member and said tool and adapted to drive one from the other, one of said parts having a longitudinal cam surface formed thereon and the other of said parts having a projection adapted to c0- act therewith and a spring resisting relative longitudinal movement of said parts to bring said cam surface into action.

ROBERT S. BLAIR. 

